const _ = require('lodash');

// 
let obj =  _.defaults({ 'a': 1 }, { 'a': 3, 'b': 2 });

console.log(obj); //{ a: 1, b: 2 }

let arr = _.partition([1,2,3,4],n=>n%2);

console.log(arr); //[ [ 1, 3 ], [ 2, 4 ] ]

let arr2 = [1,2];

let arr3 = [3,4];

let arr4 = _.concat(arr2,arr3);

// let arr4 = [...arr2,...arr3];
console.log(arr4);

